——NEPBENT iA 4950th Test Group (Nuclear) to work directly with major commands in formulating definite plans for the operation. In the months following the receipt of this preliminary book message, Headquarters, Task Group.7.4 was active in the planning stages outlining specific requirements and policies for the participating organizations. Many documents were issued during this planning phase, the following being the most importants Task Group 7.4 Planning Directive published on 17 October 1957; Task Group 7.4 Operations Plan on 6 January 1958; and Headquarters, USAF Movement Directive on 9 January 1958. The Task Group 7.4 Operations Plan, made effective as an Operations Order on 15 March 1958, was to be the directing and guiding document fer activities throughout the entire cperation. . This started q the second phase of Operation HARDTACK, that cf build-up in the fcrward area. At this time, all units came underthe control of Task Group Tod ard the majority of the time, up to the first shot, was spent on practicing and rehearsing for the first event. The nuclear testing for Operation HARDTACK commenced with the firing ofthe first event, YUCCA, on 28 April. The test series itself in- claded 35 nuclear detcnations at Eniwetok, Bikini and Johuston Islands. (See Figure 1). This is the largest nuclear test series yet conducted by the United States. Aircraft operated by or under the operational con- troi of Task Group 7.4 participated iz ‘every shot fired during EARDTACK. In support of the cperation, the aerial support elements carried 60,901 passengers and 2,626,265 pounds of cargo. 10,841 fiying hours frem the begirning of the operational phase cf COPIEDype: COPIED/DOE LANL RC These aircraft flew a total of | fer: °